This invention relates to the purification of a contaminated liquid. In one aspect, this invention relates to the recovery of an organic or inorganic diluent. In another aspect, the invention relates to purification and recycle of a hydrocarbon diluent used in a polymerization process.
Relatively pure liquids are needed for many industrial and domestic uses. For instance, high purity hydrocarbons are used as solvents in the polymerization of other organic compounds. U.S. Pat. No. 2,825,721 by Hogan et al, for instance, discloses that the polymerization of 1-olefins is carried out in the presence of solvents to produce a solid product. A solvent, can be recycled and reused in the polymerizations if it is not otherwise consumed during the reaction. A certain amount of polymeric solids, catalyst residue, and polymerization reaction reagents and by-products are entrained into or dissolved in the solvent during the reaction or during subsequent solvent removal stages. The polymer and other materials contaminate the solvent. These contaminants must be removed if the solvent is to be recycled into the polymerization process. If the contaminants are not so removed, they can build up to an unsatisfactory level and poison subsequent reactions. They may also contaminate the polymer product and damage final product physical characteristics. For instance, certain contaminants which are transferred from an impure solvent to a polymer product cause degradation of the polymer and adversely affect important physical properties such as tensile strength and color.